[FEA] cuda.core: green context / device-resource follow-ons (CUDA 13.0-13.3)

[leofang]

Summary

Green-context support in cuda.core (epic #112, closed) predates CUDA 12.8, and
_device_resources.pyx
already covers part of the 13.1 additions (SM-resource split via cuDevSmResourceSplit,
workqueue scope enums, backfill flag). This issue tracks the remaining 13.x deltas.

Underlying C APIs to cover

Symbol	Purpose
cuGreenCtxGetId(CUgreenCtx, unsigned long long* greenCtxId) (13.0)	stable green-context identifier
CUdevSmResource.minSmPartitionSize / .smCoscheduledAlignment (13.0), .flags (13.1)	new SM-resource introspection fields
cuStreamGetDevResource(CUstream, CUdevResource*, CUdevResourceType) (13.1)	query resources of the context a stream belongs to
CU_DEV_SM_RESOURCE_SPLIT_{IGNORE_SM_COSCHEDULING,MAX_POTENTIAL_CLUSTER_SIZE} (13.1)	split-by-count flags (unexposed; BACKFILL group flag is already used)
CU_DEV_SM_RESOURCE_GROUP_DEFAULT (13.1)	group flag
CUdevWorkqueueResource, CUdevWorkqueueConfigResource, CUdevResource.wq/.wqConfig/.nextResource (13.1)	workqueue resource structs/fields (the enum members are recognized, the structs are unexposed)
CU_GREEN_CTX_NONE (13.3)	green-ctx creation flag
cuCtxGetDevice_v2 / cuCtxSynchronize_v2 (13.0)	green-ctx-aware variants — audit which entry points cuda.core should call on 13.x

Design sketch (draft — needs design-meeting review)

Important

Starting point only, not a settled design — review in the cuda.core design meeting.

• GreenContext.id property (cuGreenCtxGetId).
• Stream.device_resources accessor (cuStreamGetDevResource).
• Split-by-count keyword flags on the existing split API
  (ignore_sm_coscheduling=, max_potential_cluster_size=).
• Workqueue resource wrapper types mirroring the existing SM-resource wrappers.
• Audit task: switch context-query/sync call sites to the _v2 entry points where semantics
  require it on 13.x.

Open questions for the meeting:

1. How much of the workqueue config (sharingScope, wqConcurrencyLimit, device) to surface.
2. Whether the new CUdevSmResource fields belong on the existing resource wrapper as plain
   properties (probably yes; mechanical).
3. Flag defaults and naming for split options.

References

• Driver docs: https://docs.nvidia.com/cuda/cuda-driver-api/
• Found during the CUDA 12.8 → 13.3 bindings vs. cuda.core gap sweep (2026-07-14)

-- Leo's bot